What best practices should be followed when designing PHP forms to avoid navigation issues?

When designing PHP forms, it is important to use proper form validation techniques to ensure that users enter correct data. This can help prevent navigation issues caused by users submitting incorrect or incomplete form data. Additionally, using clear error messages and providing helpful instructions can guide users through the form submission process smoothly.

// Example of form validation in PHP
if ($_SERVER["REQUEST_METHOD"] == "POST") {
    $name = $_POST["name"];
    $email = $_POST["email"];
    
    if (empty($name) || empty($email)) {
        echo "Please fill out all required fields.";
    } else {
        // Process form data here
    }
}